Fats and oils are recognized for their nutritional, functional and organoleptic properties. The food industry has been responding to consumer demand by offering an increasing variety of low-fat foods that offer the quality and taste of full-fat systems. The development of consumer acceptable low-fat food has been the result of new, as well as exciting, food ingredients created to replace some or all of the fat, without sacrificing the taste or texture consumers desire. Organoleptic properties are critical.
Fatty or oily mouth feel can be described as a combination of several basic parameters which together form the recognizable edible sensation of fattiness or oiliness. These parameters are viscosity (thickness, body, fullness), lubricity (creaminess, smoothness),absorption/adsorption (physiological effect on taste buds), and others (which may include such factors as cohesiveness, waxiness and mouthcoating).
Certain forms of cellulose have been used as a bulking agent which can be substituted for fat. One of those forms, microcrystalline cellulose (MCC) is a partially purified depolymerized form of cellulose and is obtained by treating pulps derived from fibrous plant material with mineral acid. The acid preferentially attacks the less ordered or amorphous regions of the cellulose polymer chain, thereby exposing and freeing the crystalline sites which form cellulose crystallite aggregates. The reaction mixture is washed to remove the degraded byproducts, the resulting wet-cake freed of water and the dried cellulose crystallite aggregates, or more commonly microcrystalline cellulose, recovered.
Microcrystalline cellulose is a white, odorless, tasteless, relatively free-flowing powder, insoluble in water, organic solvents, dilute alkalies and dilute acids. Small particles sized less than about 30 microns have been used in products which have been used in foods as bulking agents and as fat substitutes.
U.S. Pat. No. 4,911,946 teaches the use of a carbohydrate having a substantially spheroidal shape and a mean diameter particle size distribution between about 0.1 and about 2 microns with less than about 2% of the number of particles exceeding 3 microns as an additive for fat/cream-containing food products to replace all or a portion of the fat/cream-containing food products normally present in the food.
U.S. Pat. No. 4,814,195 teaches that particle size, oil binding capacity, and density of a bulking agent together with its taste determine its task specific suitability. According to this reference, generally, the particle size should fall within the range of 5 to 35 microns, with no measureable particles exceeding 35 microns. The oil binding capacity should fall within the range of 20 to about 45%, and the density should fall within the range of 1.3 to about 1.6 grams per cubic centimeter.
According to the '195 patent, commercially available cellulose, alpha-cellulose, micro-fibrillated cellulose, natural fibers, and Avicel.RTM. microcrystalline cellulose have large porous surface areas; thus they absorb excessive amounts of oil and are not suitable for use in the reduced calorie peanut butter products of the present invention.
That patent further teaches that one way to minimize the oil-binding capacity of commercially available microcrystalline cellulose is to agglomerate the submicron constituent particles to form smooth-surfaced aggregates having a substantially increased effective particle size and effectively decreased oil-binding capacity. There is no teaching that these particles be spherical or that this can be done with non-submicron particles.
A method of producing spherical particulates that is attracting the increased attention of the pharmaceutical industry is that of spheronization. The essential features of this technique typically involves the steps of: forming a dry blend of powdered components; wetting the dry blend with a liquid, usually aqueous, in the presence of a binding agent to give a plastic-like mass or granulation; extruding the mass through a screen or die to form a spaghetti extrudate; cutting the extrudate in short cylinders followed by a rounding stage in which the cylinders are rolled on a grooved surface into spheres. For more detailed information on the process reference is made to "A new Technique for the Production of Spherical Particles" by A. D. Reynolds in Manufacturing Chemist & Aerosol News, Jun. 1970.